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Vázquez-Hernández M, Leedom SL, Keiler KC, Bandow JE. Physiology of trans-translation deficiency in Bacillus subtilis - a comparative proteomics study. Proteomics 2023; 23:e2200474. [PMID: 37496314 DOI: 10.1002/pmic.202200474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 06/09/2023] [Accepted: 06/12/2023] [Indexed: 07/28/2023]
Abstract
trans-Translation is the most effective ribosome rescue system known in bacteria. While it is essential in some bacteria, Bacillus subtilis possesses two additional alternative ribosome rescue mechanisms that require the proteins BrfA or RqcH. To investigate the physiology of trans-translation deficiency in the model organism B. subtilis, we compared the proteomes of B. subtilis 168 and a ΔssrA mutant in the mid-log phase using gel-free label-free quantitative proteomics. In chemically defined medium, the growth rate of the ssrA deletion mutant was 20% lower than that of B. subtilis 168. An 35 S-methionine incorporation assay demonstrated that protein synthesis rates were also lower in the ΔssrA strain. Alternative rescue factors were not detected. Among the 34 proteins overrepresented in the mutant strain were eight chemotaxis proteins. Indeed, both on LB agar and minimal medium the ΔssrA strain showed an altered motility and chemotaxis phenotype. Despite the lower growth rate, in the mutant proteome ribosomal proteins were more abundant while proteins related to amino acid biosynthesis were less abundant than in the parental strain. This overrepresentation of ribosomal proteins coupled with a lower protein synthesis rate and down-regulation of precursor supply reflects the slow ribosome recycling in the trans-translation-deficient mutant.
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Affiliation(s)
| | - Stephanie L Leedom
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Kenneth C Keiler
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Julia Elisabeth Bandow
- Applied Microbiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
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Subhadra B, Cao D, Jensen R, Caswell C, Inzana TJ. Identification and initial characterization of Hfq-associated sRNAs in Histophilus somni strain 2336. PLoS One 2023; 18:e0286158. [PMID: 37220152 DOI: 10.1371/journal.pone.0286158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 05/09/2023] [Indexed: 05/25/2023] Open
Abstract
Small RNAs (sRNA), in association with the global chaperone regulator Hfq, positively or negatively regulate gene expression in bacteria. For this study, Histophilus somni sRNAs that bind to Hfq were identified and then partially characterized. The Hfq-associated sRNAs in H. somni were isolated and identified by co-immunoprecipitation using anti-Hfq antibody, followed by sRNA sequencing. Sequence analysis of the sRNA samples identified 100 putative sRNAs, out of which 16 were present in pathogenic strain 2336, but not in non-pathogenic strain 129Pt. Bioinformatic analyses suggested that the sRNAs HS9, HS79, and HS97 could bind to many genes putatively involved in virulence/biofilm formation. Furthermore, multi-sequence alignment of the sRNA regions in the genome revealed that HS9 and HS97 could interact with sigma 54, which is a transcription factor linked to important bacterial traits, including motility, virulence, and biofilm formation. Northern blotting was used to determine the approximate size, abundance and any processing events attributed to the sRNAs. Selected sRNA candidates were confirmed to bind Hfq, as determined by electrophoretic mobility shift assays using sRNAs synthesized by in vitro transcription and recombinant Hfq. The exact transcriptional start site of the sRNA candidates was determined by RNA ligase-mediated rapid amplification of cDNA ends, followed by cloning and sequencing. This is the first investigation of H. somni sRNAs that show they may have important regulatory roles in virulence and biofilm formation.
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Affiliation(s)
- Bindu Subhadra
- College of Veterinary Medicine, Long Island University, Brookville, New York, United States of America
| | - Dianjun Cao
- College of Veterinary Medicine, Long Island University, Brookville, New York, United States of America
| | - Roderick Jensen
- College of Science, Virginia Tech, Blacksburg, VA, United States of America
| | - Clayton Caswell
- Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States of America
| | - Thomas J Inzana
- College of Veterinary Medicine, Long Island University, Brookville, New York, United States of America
- Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States of America
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Duan H, Zhang X, Figeys D. An emerging field: Post-translational modification in microbiome. Proteomics 2023; 23:e2100389. [PMID: 36239139 DOI: 10.1002/pmic.202100389] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 09/27/2022] [Accepted: 09/28/2022] [Indexed: 11/11/2022]
Abstract
Post-translational modifications (PTMs) play an essential role in most biological processes. PTMs on human proteins have been extensively studied. Studies on bacterial PTMs are emerging, which demonstrate that bacterial PTMs are different from human PTMs in their types, mechanisms and functions. Few PTM studies have been done on the microbiome. Here, we reviewed several studied PTMs in bacteria including phosphorylation, acetylation, succinylation, glycosylation, and proteases. We discussed the enzymes responsible for each PTM and their functions. We also summarized the current methods used to study microbiome PTMs and the observations demonstrating the roles of PTM in the microbe-microbe interactions within the microbiome and their interactions with the environment or host. Although new methods and tools for PTM studies are still needed, the existing technologies have made great progress enabling a deeper understanding of the functional regulation of the microbiome. Large-scale application of these microbiome-wide PTM studies will provide a better understanding of the microbiome and its roles in the development of human diseases.
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Affiliation(s)
- Haonan Duan
- School of Pharmaceutical Sciences, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada.,Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Xu Zhang
- Center for Biologics Evaluation, Biologic and Radiopharmaceutical Drugs Directorate, Health Products and Food Branch, Health Canada, Ottawa, Canada
| | - Daniel Figeys
- School of Pharmaceutical Sciences, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada.,Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Ontario, Canada
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Abstract
Despite having a highly reduced genome, Chlamydia trachomatis undergoes a complex developmental cycle in which the bacteria differentiate between the following two functionally and morphologically distinct forms: the infectious, nonreplicative elementary body (EB) and the noninfectious, replicative reticulate body (RB). The transitions between EBs and RBs are not mediated by division events that redistribute intracellular proteins. Rather, both primary (EB to RB) and secondary (RB to EB) differentiation likely require bulk protein turnover. One system for targeted protein degradation is the trans-translation system for ribosomal rescue, where polypeptides stalled during translation are marked with an SsrA tag encoded by a hybrid tRNA-mRNA, tmRNA. ClpX recognizes the SsrA tag, leading to ClpXP-mediated degradation. We hypothesize that ClpX functions in chlamydial differentiation through targeted protein degradation. We found that mutation of a key residue (R230A) within the specific motif in ClpX associated with the recognition of SsrA-tagged substrates resulted in abrogated secondary differentiation while not reducing chlamydial replication or developmental cycle progression as measured by transcripts. Furthermore, inhibition of trans-translation through chemical and targeted genetic approaches also impeded chlamydial development. Knockdown of tmRNA and subsequent complementation with an allele mutated in the SsrA tag closely phenocopied the overexpression of ClpXR230A, thus suggesting that ClpX recognition of SsrA-tagged substrates plays a critical function in secondary differentiation. Taken together, these data provide mechanistic insight into the requirements for transitions between chlamydial developmental forms. IMPORTANCE Chlamydia trachomatis is the leading cause of bacterial sexually transmitted infections and preventable infectious blindness. This unique organism undergoes developmental transitions between infectious, nondividing forms and noninfectious, dividing forms. Therefore, the chlamydial developmental cycle is an attractive target for Chlamydia-specific antibiotics, which would minimize effects of broad-spectrum antibiotics on the spread of antibiotic resistance in other organisms. However, the lack of knowledge about chlamydial development on a molecular level impedes the identification of specific, druggable targets. This work describes a mechanism through which both the fundamental processes of trans-translation and proteomic turnover by ClpXP contribute to chlamydial differentiation, a critical facet of chlamydial growth and survival. Given the almost universal presence of trans-translation and ClpX in eubacteria, this mechanism may be conserved in developmental cycles of other bacterial species. Additionally, this study expands the fields of trans-translation and Clp proteases by emphasizing the functional diversity of these systems throughout bacterial evolution.
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Liu P, Chang H, Xu Q, Wang D, Tang Y, Hu X, Lin M, Liu Z. Peptide Aptamer PA3 Attenuates the Viability of Aeromonas veronii by Hindering of Small Protein B-Outer Membrane Protein A Signal Pathway. Front Microbiol 2022; 13:900234. [PMID: 35663889 PMCID: PMC9159911 DOI: 10.3389/fmicb.2022.900234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 04/12/2022] [Indexed: 11/15/2022] Open
Abstract
The small protein B (SmpB), previously acting as a ribosome rescue factor for translation quality control, is required for cell viability in bacteria. Here, our study reveals that SmpB possesses new function which regulates the expression of outer membrane protein A (ompA) gene as a transcription factor in Aeromonas veronii. The deletion of SmpB caused the lower transcription expression of ompA by Quantitative Real-Time PCR (qPCR). Electrophoretic mobility shift assay (EMSA) and DNase I Footprinting verified that the SmpB bound at the regions of −46 to −28 bp, −18 to +4 bp, +21 to +31 bp, and +48 to +59 bp of the predicted ompA promoter (PompA). The key sites C52AT was further identified to interact with SmpB when PompA was fused with enhanced green fluorescent protein (EGFP) and co-transformed with SmpB expression vector for the fluorescence detection, and the result was further confirmed in microscale thermophoresis (MST) assays. Besides, the amino acid sites G11S, F26I, and K152 in SmpB were the key sites for binding to PompA. In order to further develop peptide antimicrobial agents, the peptide aptamer PA3 was screened from the peptide aptamer (PA) library by bacterial two-hybrid method. The drug sensitivity test showed that PA3 effectively inhibited the growth of A. veronii. In summary, these results demonstrated that OmpA was a good drug target for A. veronii, which was regulated by the SmpB protein and the selected peptide aptamer PA3 interacted with OmpA protein to disable SmpB-OmpA signal pathway and inhibited A. veronii, suggesting that it could be used as an antimicrobial agent for the prevention and treatment of pathogens.
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Affiliation(s)
- Peng Liu
- School of Life Sciences, Hainan University, Haikou, China
- Center for Medical Innovation, School of Basic Medical Science, Guangxi University of Chinese Medicine, Nanning, China
| | - Huimin Chang
- School of Life Sciences, Hainan University, Haikou, China
| | - Qi Xu
- School of Life Sciences, Hainan University, Haikou, China
| | - Dan Wang
- School of Life Sciences, Hainan University, Haikou, China
| | - Yanqiong Tang
- School of Life Sciences, Hainan University, Haikou, China
- One Health Institute, Hainan University, Haikou, China
| | - Xinwen Hu
- School of Life Sciences, Hainan University, Haikou, China
| | - Min Lin
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zhu Liu
- School of Life Sciences, Hainan University, Haikou, China
- One Health Institute, Hainan University, Haikou, China
- *Correspondence: Zhu Liu,
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Extensive epigenetic modification with large-scale chromosomal and plasmid recombination characterise the Legionella longbeachae serogroup 1 genome. Sci Rep 2022; 12:5810. [PMID: 35388097 PMCID: PMC8987031 DOI: 10.1038/s41598-022-09721-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 03/15/2022] [Indexed: 11/08/2022] Open
Abstract
Legionella longbeachae is an environmental bacterium that is the most clinically significant Legionella species in New Zealand (NZ), causing around two-thirds of all notified cases of Legionnaires’ disease. Here we report the sequencing and analysis of the geo-temporal genetic diversity of 54 L. longbeachae serogroup 1 (sg1) clinical isolates, derived from cases from around NZ over a 22-year period, including one complete genome and its associated methylome. The 54 sg1 isolates belonged to two main clades that last shared a common ancestor between 95 BCE and 1694 CE. There was diversity at the genome-structural level, with large-scale arrangements occurring in some regions of the chromosome and evidence of extensive chromosomal and plasmid recombination. This includes the presence of plasmids derived from recombination and horizontal gene transfer between various Legionella species, indicating there has been both intra- and inter-species gene flow. However, because similar plasmids were found among isolates within each clade, plasmid recombination events may pre-empt the emergence of new L. longbeachae strains. Our complete NZ reference genome consisted of a 4.1 Mb chromosome and a 108 kb plasmid. The genome was highly methylated with two known epigenetic modifications, m4C and m6A, occurring in particular sequence motifs within the genome.
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Identification and characterisation of sPEPs in Cryptococcus neoformans. Fungal Genet Biol 2022; 160:103688. [PMID: 35339703 DOI: 10.1016/j.fgb.2022.103688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/02/2022] [Accepted: 03/21/2022] [Indexed: 11/24/2022]
Abstract
Short open reading frame (sORF)-encoded peptides (sPEPs) have been found across a wide range of genomic locations in a variety of species. To date, their identification, validation, and characterisation in the human fungal pathogen Cryptococcus neoformans has been limited due to a lack of standardised protocols. We have developed an enrichment process that enables sPEP detection within a protein sample from this polysaccharide-encapsulated yeast, and implemented proteogenomics to provide insights into the validity of predicted and hypothetical sORFs annotated in the C. neoformans genome. Novel sORFs were discovered within the 5' and 3' UTRs of known transcripts as well as in "non-coding" RNAs. One novel candidate, dubbed NPB1, that resided in an RNA annotated as "non-coding", was chosen for characterisation. Through the creation of both specific point mutations and a full deletion allele, the function of the new sPEP, Npb1, was shown to resemble that of the bacterial trans-translation protein SmpB.
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Costa SM, Saramago M, Matos RG, Arraiano CM, Viegas SC. How hydrolytic exoribonucleases impact human disease: Two sides of the same story. FEBS Open Bio 2022. [PMID: 35247037 DOI: 10.1002/2211-5463.13392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 02/16/2022] [Accepted: 03/03/2022] [Indexed: 11/05/2022] Open
Abstract
RNAs are extremely important molecules inside the cell which perform many different functions. For example, messenger RNAs, transfer RNAs, and ribosomal RNAs are involved in protein synthesis, whereas non-coding RNAs have numerous regulatory roles. Ribonucleases are the enzymes responsible for the processing and degradation of all types of RNAs, having multiple roles in every aspect of RNA metabolism. However, the involvement of RNases in disease is still not well understood. This review focuses on the involvement of the RNase II/RNB family of 3'-5' exoribonucleases in human disease. This can be attributed to direct effects, whereby mutations in the eukaryotic enzymes of this family (Dis3 (or Rrp44), Dis3L1 (or Dis3L), and Dis3L2) are associated with a disease, or indirect effects, whereby mutations in the prokaryotic counterparts of RNase II/RNB family (RNase II and/or RNase R) affect the physiology and virulence of several human pathogens. In this review, we will compare the structural and biochemical characteristics of the members of the RNase II/RNB family of enzymes. The outcomes of mutations impacting enzymatic function will be revisited, in terms of both the direct and indirect effects on disease. Furthermore, we also describe the SARS-CoV-2 viral exoribonuclease and its importance to combat COVID-19 pandemic. As a result, RNases may be a good therapeutic target to reduce bacterial and viral pathogenicity. These are the two perspectives on RNase II/RNB family enzymes that will be presented in this review.
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Affiliation(s)
- Susana M Costa
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, EAN, 2780-157, Oeiras, Portugal
| | - Margarida Saramago
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, EAN, 2780-157, Oeiras, Portugal
| | - Rute G Matos
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, EAN, 2780-157, Oeiras, Portugal
| | - Cecília M Arraiano
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, EAN, 2780-157, Oeiras, Portugal
| | - Sandra C Viegas
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, EAN, 2780-157, Oeiras, Portugal
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Ren H, Zhang J, Zhou J, Xu C, Fan Z, Pan X, Li S, Liang Y, Chen S, Xu J, Wang P, Zhang Y, Zhu G, Liu H, Jin Y, Bai F, Cheng Z, Pletzer D, Wu W. Synergistic bactericidal activities of tobramycin with ciprofloxacin and azithromycin against Klebsiella pneumoniae. J Antibiot (Tokyo) 2021; 74:528-537. [PMID: 34050325 DOI: 10.1038/s41429-021-00427-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 11/09/2022]
Abstract
Trans-translation is a unique bacterial ribosome rescue system that plays important roles in the tolerance to environmental stresses. It is composed of an ssrA-encoded tmRNA and a protein SmpB. In this study, we examined the role of trans-translation in antibiotic tolerance in Klebsiella pneumoniae and explored whether the inhibition of this mechanism could enhance the bactericidal activities of antibiotics. We found that deletion of the ssrA gene reduced the survival of K. pneumoniae after treatment with kanamycin, tobramycin, azithromycin, and ciprofloxacin, indicating an important role of the trans-translation in bacterial antibiotic tolerance. By using a modified ssrA gene with a 6×His tag we demonstrated that tobramycin suppressed the azithromycin and ciprofloxacin-elicited activation of trans-translation. The results were further confirmed with a trans-translation reporter system that is composed of a normal mCherry gene and a gfp gene without the stop codon. Compared to each individual antibiotic, combination of tobramycin with azithromycin or ciprofloxacin synergistically enhanced the killing activities against planktonic K. pneumoniae cells and improved bacterial clearance in a murine cutaneous abscess infection model. In addition, the combination of tobramycin and ciprofloxacin increased the bactericidal activities against biofilm-associated cells. Overall, our results suggest that the combination of tobramycin with azithromycin or ciprofloxacin is a promising strategy in combating K. pneumoniae infections.
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Affiliation(s)
- Huan Ren
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Jingyi Zhang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Jingyi Zhou
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Congjuan Xu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Zheng Fan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Xiaolei Pan
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Shouyi Li
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Yuying Liang
- Department of laboratory medicine, 5th medical center of PLA general hospital, Beijing, 100071, China
| | - Shuiping Chen
- Department of laboratory medicine, 5th medical center of PLA general hospital, Beijing, 100071, China
| | - Jun Xu
- NHC Key Laboratory of Hormones and Development (Tianjin Medical University), Tianjin Key Laboratory of Metabolic Diseases, Diabetic foot Department, Tianjin Medical University Metabolic Disease Hospital & Chu Hsien-I Memorial Hospital, Tianjin, 300070, China
| | - Penghua Wang
- NHC Key Laboratory of Hormones and Development (Tianjin Medical University), Tianjin Key Laboratory of Metabolic Diseases, Diabetic foot Department, Tianjin Medical University Metabolic Disease Hospital & Chu Hsien-I Memorial Hospital, Tianjin, 300070, China
| | - Yanhong Zhang
- Nankai University Affiliated Hospital (Tianjin Forth Hospital), Tianjin, 300222, China
| | - Guangbo Zhu
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, 300121, China
| | - Huimin Liu
- Tianjin Union Medical Center, Nankai University Affiliated Hospital, Tianjin, 300121, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Daniel Pletzer
- Department of Microbiology & Immunology, University of Otago, Dunedin, 9054, New Zealand
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China.
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Transposon Insertion Sequencing in a Clinical Isolate of Legionella pneumophila Identifies Essential Genes and Determinants of Natural Transformation. J Bacteriol 2021; 203:JB.00548-20. [PMID: 33168636 PMCID: PMC7811196 DOI: 10.1128/jb.00548-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 11/04/2020] [Indexed: 02/07/2023] Open
Abstract
Legionella pneumophila is the etiologic agent of a severe form of nosocomial and community-acquired pneumonia in humans. The environmental life traits of L. pneumophila are essential to its ability to accidentally infect humans. Legionella pneumophila is a Gram-negative bacterium ubiquitous in freshwater environments which, if inhaled, can cause a severe pneumonia in humans. The emergence of L. pneumophila is linked to several traits selected in the environment, the acquisition of some of which involved intra- and interkingdom horizontal gene transfer events. Transposon insertion sequencing (TIS) is a powerful method to identify the genetic basis of selectable traits as well as to identify fitness determinants and essential genes, which are possible antibiotic targets. TIS has not yet been used to its full power in L. pneumophila, possibly because of the difficulty of obtaining a high-saturation transposon insertion library. Indeed, we found that isolates of sequence type 1 (ST1), which includes the commonly used laboratory strains, are poorly permissive to saturating mutagenesis by conjugation-mediated transposon delivery. In contrast, we obtained high-saturation libraries in non-ST1 clinical isolates, offering the prospect of using TIS on unaltered L. pneumophila strains. Focusing on one of them, we then used TIS to identify essential genes in L. pneumophila. We also revealed that TIS could be used to identify genes controlling vertical transmission of mobile genetic elements. We then applied TIS to identify all the genes required for L. pneumophila to develop competence and undergo natural transformation, defining the set of major and minor type IV pilins that are engaged in DNA uptake. This work paves the way for the functional exploration of the L. pneumophila genome by TIS and the identification of the genetic basis of other life traits of this species. IMPORTANCELegionella pneumophila is the etiologic agent of a severe form of nosocomial and community-acquired pneumonia in humans. The environmental life traits of L. pneumophila are essential to its ability to accidentally infect humans. A comprehensive identification of their genetic basis could be obtained through the use of transposon insertion sequencing. However, this powerful approach had not been fully implemented in L. pneumophila. Here, we describe the successful implementation of the transposon-sequencing approach in a clinical isolate of L. pneumophila. We identify essential genes, potential drug targets, and genes required for horizontal gene transfer by natural transformation. This work represents an important step toward identifying the genetic basis of the many life traits of this environmental and pathogenic species.
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Peng M, Cao X, Tang Y, Li H, Ma X, Liu Z. Large-scale identification of trans-translation substrates targeted by tmRNA in Aeromonas veronii. Microb Pathog 2020; 145:104226. [PMID: 32353577 DOI: 10.1016/j.micpath.2020.104226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/18/2020] [Accepted: 04/20/2020] [Indexed: 10/24/2022]
Abstract
Transfer-messenger RNA (tmRNA) is ubiquitous in bacteria, acting as the core component for the trans-translation system that contributes to label the aberrantly synthesized peptides for degradation and to release the stalled ribosomes. Deletion of tmRNA causes a variety of phenotypes related to important physiological processes in bacteria. To illustrate the molecular mechanism of the versatility of tmRNA in aquatic pathogen Aeromonas veronii, we mutated the C-terminal nucleotides of tmRNA (MutmRNA) for encoding a tag containing six histidine residues (His6tag), so as to capture and enrich the trans-translation substrates from the cell lysates through a Ni2+-NTA affinity chromatograph. The results showed that the concentrated substrates were detected as distinct and specific bands in western blotting using anti-His antibody, demonstrating that specific defective mRNAs were frequently and intensively rescued by trans-translation during the translation process in A. veronii. The substrates were analyzed by LC-MS/MS and further identified by searching a theoretically constructed database specific for A. veronii. Total of 24 potential substrates were identified, with various functions involved in metabolism, as well as structure and signal-based cellular events. Among the identified substrates, PspA and AsmA were labeled by Flag, and expressed in the presence of the modified trans-translation system in E. coli. Their labelings with MutmRNA were validated by purification through Ni2+-NTA column followed by western blotting using anti-Flag antibody. This study provided the most abundant set of endogenous targets for tmRNA in A. veronii, and facilitated further investigations about the molecular mechanism and signal pathway of tmRNA-mediated trans-translation.
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Affiliation(s)
- Muzhi Peng
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Life and Pharmaceutical Sciences, Hainan University, 570228, Haikou, China
| | - Xin Cao
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Life and Pharmaceutical Sciences, Hainan University, 570228, Haikou, China
| | - Yanqiong Tang
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Life and Pharmaceutical Sciences, Hainan University, 570228, Haikou, China
| | - Hong Li
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Life and Pharmaceutical Sciences, Hainan University, 570228, Haikou, China
| | - Xiang Ma
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Life and Pharmaceutical Sciences, Hainan University, 570228, Haikou, China.
| | - Zhu Liu
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Life and Pharmaceutical Sciences, Hainan University, 570228, Haikou, China.
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12
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Release factor-dependent ribosome rescue by BrfA in the Gram-positive bacterium Bacillus subtilis. Nat Commun 2019; 10:5397. [PMID: 31776341 PMCID: PMC6881298 DOI: 10.1038/s41467-019-13408-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 11/07/2019] [Indexed: 12/14/2022] Open
Abstract
Rescue of the ribosomes from dead-end translation complexes, such as those on truncated (non-stop) mRNA, is essential for the cell. Whereas bacteria use trans-translation for ribosome rescue, some Gram-negative species possess alternative and release factor (RF)-dependent rescue factors, which enable an RF to catalyze stop-codon-independent polypeptide release. We now discover that the Gram-positive Bacillus subtilis has an evolutionarily distinct ribosome rescue factor named BrfA. Genetic analysis shows that B. subtilis requires the function of either trans-translation or BrfA for growth, even in the absence of proteotoxic stresses. Biochemical and cryo-electron microscopy (cryo-EM) characterization demonstrates that BrfA binds to non-stop stalled ribosomes, recruits homologous RF2, but not RF1, and induces its transition into an open active conformation. Although BrfA is distinct from E. coli ArfA, they use convergent strategies in terms of mode of action and expression regulation, indicating that many bacteria may have evolved as yet unidentified ribosome rescue systems. In bacteria, the conserved trans-translation system serves as the primary pathway of ribosome rescue, but many species can also use alternative rescue pathways. Here the authors report that in B. subtilis, the rescue factor BrfA binds to non-stop stalled ribosomes, recruits RF2 but not RF1, and induces transition of the ribosome into an open active conformation.
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Tresse C, Radigue R, Gomes Von Borowski R, Thepaut M, Hanh Le H, Demay F, Georgeault S, Dhalluin A, Trautwetter A, Ermel G, Blanco C, van de Weghe P, Jean M, Giard JC, Gillet R. Synthesis and evaluation of 1,3,4-oxadiazole derivatives for development as broad-spectrum antibiotics. Bioorg Med Chem 2019; 27:115097. [DOI: 10.1016/j.bmc.2019.115097] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 09/06/2019] [Accepted: 09/09/2019] [Indexed: 10/26/2022]
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Huang Y, Alumasa JN, Callaghan LT, Baugh RS, Rae CD, Keiler KC, McGillivray SM. A Small-Molecule Inhibitor of trans-Translation Synergistically Interacts with Cathelicidin Antimicrobial Peptides To Impair Survival of Staphylococcus aureus. Antimicrob Agents Chemother 2019; 63:e02362-18. [PMID: 30917982 PMCID: PMC6437501 DOI: 10.1128/aac.02362-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 01/16/2019] [Indexed: 12/24/2022] Open
Abstract
Staphylococcus aureus is a leading cause of infection in the United States, and due to the rapid development of resistance, new antibiotics are constantly needed. trans-Translation is a particularly promising antibiotic target because it is conserved in many bacterial species, is critical for bacterial survival, and is unique among prokaryotes. We have investigated the potential of KKL-40, a small-molecule inhibitor of trans-translation, and find that it inhibits both methicillin-susceptible and methicillin-resistant strains of S. aureus KKL-40 is also effective against Gram-positive pathogens, including a vancomycin-resistant strain of Enterococcus faecalis, Bacillus subtilis, and Streptococcus pyogenes, although its performance with Gram-negative pathogens is mixed. KKL-40 synergistically interacts with the human antimicrobial peptide LL-37, a member of the cathelicidin family, to inhibit S. aureus but not other antibiotics tested, including daptomycin, kanamycin, or erythromycin. KKL-40 is not cytotoxic to HeLa cells at concentrations that are 100-fold higher than the effective MIC. We also find that S. aureus develops minimal resistance to KKL-40 even after multiday passage at sublethal concentrations. Therefore, trans-translation inhibitors could be a particularly promising drug target against S. aureus, not only because of their ability to inhibit bacterial growth but also because of their potential to simultaneously render S. aureus more susceptible to host antimicrobial peptides.
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Affiliation(s)
- Yueyang Huang
- Department of Biology, Texas Christian University, Fort Worth, Texas, USA
| | - John N Alumasa
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Lauren T Callaghan
- Department of Biology, Texas Christian University, Fort Worth, Texas, USA
| | - R Samuel Baugh
- Department of Biology, Texas Christian University, Fort Worth, Texas, USA
| | - Christopher D Rae
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Kenneth C Keiler
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA
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KKL-35 Exhibits Potent Antibiotic Activity against Legionella Species Independently of trans-Translation Inhibition. Antimicrob Agents Chemother 2018; 62:AAC.01459-17. [PMID: 29158279 PMCID: PMC5786812 DOI: 10.1128/aac.01459-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 11/04/2017] [Indexed: 11/20/2022] Open
Abstract
trans-Translation is a ribosome-rescue system that is ubiquitous in bacteria. Small molecules defining a new family of oxadiazole compounds that inhibit trans-translation have been found to have broad-spectrum antibiotic activity. We sought to determine the activity of KKL-35, a potent member of the oxadiazole family, against the human pathogen Legionella pneumophila and other related species that can also cause Legionnaires' disease (LD). Consistent with the essential nature of trans-translation in L. pneumophila, KKL-35 inhibited the growth of all tested strains at submicromolar concentrations. KKL-35 was also active against other LD-causing Legionella species. KKL-35 remained equally active against L. pneumophila mutants that have evolved resistance to macrolides. KKL-35 inhibited the multiplication of L. pneumophila in human macrophages at several stages of infection. No resistant mutants could be obtained, even during extended and chronic exposure. Surprisingly, KKL-35 was not synergistic with other ribosome-targeting antibiotics and did not induce the filamentation phenotype observed in cells defective for trans-translation. Importantly, KKL-35 remained active against L. pneumophila mutants expressing an alternate ribosome-rescue system and lacking transfer-messenger RNA, the essential component of trans-translation. These results indicate that the antibiotic activity of KKL-35 is not related to the specific inhibition of trans-translation and its mode of action remains to be identified. In conclusion, KKL-35 is an effective antibacterial agent against the intracellular pathogen L. pneumophila with no detectable resistance development. However, further studies are needed to better understand its mechanism of action and to assess further the potential of oxadiazoles in treatment.
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Macé K, Demay F, Guyomar C, Georgeault S, Giudice E, Goude R, Trautwetter A, Ermel G, Blanco C, Gillet R. A Genetic Tool to Quantify trans-Translation Activity in Vivo. J Mol Biol 2017; 429:3617-3625. [PMID: 29031699 DOI: 10.1016/j.jmb.2017.10.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/29/2017] [Accepted: 10/08/2017] [Indexed: 11/17/2022]
Abstract
In bacteria, trans-translation is the main quality control mechanism for rescuing ribosomes arrested during translation. This key process is universally conserved and plays a critical role in the viability and virulence of many pathogens. We developed a reliable in vivo double-fluorescence reporter system for the simultaneous quantification of both trans-translation and the associated proteolysis activities in bacteria. The assay was validated using mutant bacteria lacking tmRNA, SmpB, and the ClpP protease. Both antisense tmRNA-binding RNA and a peptide mimicking the SmpB C-terminal tail proved to be potent inhibitors of trans-translation in vivo. The double-fluorescent reporter was also tested with KKL-35, an oxadiazole derivative that is supposed to be a promising trans-translation inhibitor, and it surprisingly turns out that trans-translation is not the only target of KKL-35 in vivo.
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Affiliation(s)
- Kevin Macé
- Univ. Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Fanny Demay
- Univ. Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Charlotte Guyomar
- Univ. Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Sylvie Georgeault
- Univ. Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Emmanuel Giudice
- Univ. Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Renan Goude
- Univ. Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Annie Trautwetter
- Univ. Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Gwennola Ermel
- Univ. Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Carlos Blanco
- Univ. Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France.
| | - Reynald Gillet
- Univ. Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France.
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Huter P, Müller C, Arenz S, Beckert B, Wilson DN. Structural Basis for Ribosome Rescue in Bacteria. Trends Biochem Sci 2017. [PMID: 28629612 DOI: 10.1016/j.tibs.2017.05.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Ribosomes that translate mRNAs lacking stop codons become stalled at the 3' end of the mRNA. Recycling of these stalled ribosomes is essential for cell viability. In bacteria three ribosome rescue systems have been identified so far, with the most ubiquitous and best characterized being the trans-translation system mediated by transfer-messenger RNA (tmRNA) and small protein B (SmpB). The two additional rescue systems present in some bacteria employ alternative rescue factor (Arf) A and release factor (RF) 2 or ArfB. Recent structures have revealed how ArfA mediates ribosome rescue by recruiting the canonical termination factor RF2 to ribosomes stalled on truncated mRNAs. This now provides us with the opportunity to compare and contrast the available structures of all three bacterial ribosome rescue systems.
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Affiliation(s)
- Paul Huter
- Gene Center, Department of Biochemistry and Center for Integrated Protein Science Munich (CiPSM), Feodor-Lynenstr. 25, 81377 München, Germany
| | - Claudia Müller
- Gene Center, Department of Biochemistry and Center for Integrated Protein Science Munich (CiPSM), Feodor-Lynenstr. 25, 81377 München, Germany
| | - Stefan Arenz
- Gene Center, Department of Biochemistry and Center for Integrated Protein Science Munich (CiPSM), Feodor-Lynenstr. 25, 81377 München, Germany
| | - Bertrand Beckert
- Gene Center, Department of Biochemistry and Center for Integrated Protein Science Munich (CiPSM), Feodor-Lynenstr. 25, 81377 München, Germany; Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
| | - Daniel N Wilson
- Gene Center, Department of Biochemistry and Center for Integrated Protein Science Munich (CiPSM), Feodor-Lynenstr. 25, 81377 München, Germany; Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany.
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